let set1=new Set();
console.log(set1);

let set2=new Set([1,2,3]);
console.log(set2);

let arr=[1,2,3,2,3];
let set3=new Set(arr);
console.log(set3);

let brr=[1,2,'1','a'];
let set4=new Set(brr);
console.log(set4);

let set5=new Set();
set5.add(1);
set5.add('你好');
set5.add('3');
set5.delete('3');
//set5.clear();
console.log(set5);
console.log(set5.size);
console.log(set5.has('你好'));

let set6=new Set(['a','b','c']);
for(let k of set6.keys()){
    console.log(k);
}
for(let val of set6.values()){
    console.log(val);
}

let weakset1=new WeakSet();
weakset1.add({});
console.log(weakset1);
